The objective of this work is understanding the molecular and cellular regulation of hemoglobin function. This is approached by the study of abnormal hemoglobins, sheep and goat hemoglobin, whole blood oxygen affinity of pure hemoglobin. In the past year a report of Hemoglobin McKees Rocks, a mutant with exceedingly high oxygen affinity has been completed, and the measurement of the oxygen dissociation curve of normal human blood has been accomplished. The precision of the latter data is of sufficient quality that for the first time computer analysis of blood oxygenation data can be carried out in order to evaluate the relation between the function of pure hemoglobin and red cells.